Wave

Wave is a boost modifier in which the arrows move up and down in an oscillating motion until they reach the receptors, in wave-like motions. If the Wave option is turned on, then all speed options are dispelled.

If you AAd any EVOLVED song on Extra Stage with the Wave option on, Tohoku EVOLVED would not be accessed as the Encore Extra Stage.

In DanceDanceRevolution X3 VS 2ndMIX, AAing any EVOLVED song on Extra Stage with the Wave option on, which would have normally set Tohoku EVOLVED as the Encore Extra Stage, just ended the credit at the Extra Stage rather than continue on to the Encore Extra Stage, thus denying the player access to Tohoku EVOLVED as the Encore Extra Stage. This is most likely a reference of the March 2011 tsunami that struck the northern region of Japan.